Field of the Invention
The instant invention relates generally to wet electrostatic precipitator devices and more specifically to the exact design of the electrostatic elements and the spacial relationship between the electrostatic ionizing elements and the cooperating honeycomb collector passage ways.
A wet electrostatic precipitator is an apparatus which separates suspended particles of solid or liquid material from a gas stream. It is widely used in air pollution control technology, chemical and metallurgical industries.
The separation process consists of the following steps:
1. Electrical charging of suspended particles is accomplished by negative ions produced by so called corona discharge which in effect is a current flow through an air gap between a positive (usually grounded) electrode and a negative ionizing electrode. These electrodes are connected to a source of high voltage direct current HVDC. The value of HVDC depends on the distance between the electrodes and the properties of the gas stream to be processed. For industrial equipment where the gases can be very contaminated with coarse and sticky particles, a relatively large gap distance and high voltages are essential for long lasting and reliable operation and usually are respectively in the range of 4" to 6" and 30,000 to 75,000 volts;
2. Collection of the charged particles on the surface of positive collecting electrodes. Electrostatic attraction forces between negative particles and the positive collector are caused to create a so called "migration velocity" perpendicular to the direction of the gas flow. This velocity causes the particles to strike the surface of the collecting electrodes. At this point the particles give way to negative charge on the "grounded" collector and charges from all particles in the form of returning current flow arrive back to the high voltage transformer to complete the electrical circuit; and
3. Removal of collected particles from the collecting electrodes surface. In the wet electrostatic precipitator, this is accomplished by washing away the collected particles continuously using collected liquid mist from the gas stream. This liquid mist is introduced into the gas flow for cooling and rescrubbing action before the collecting section of the wet electrostatic precipitator device and after the wet electrostatic precipitator device, solely for cleaning contaminates from the collecting electrodes.
The three steps described above are generally utilized in the vertical tubular design of wet electrostatic precipitator systems, where the collecting electrodes are in the shape of tubes and the ionizing electrodes are in the shape of round cylindrical rods located at the center of each respective tube.